US2402370A - Method of producing magnesium compounds - Google Patents

Description

Patented June 18,

UNITED STATES PATENT OFFICE.

METHOD OF PRODUCING MAGNEF COMPOUNDS Henry a. Chalmers, New York, N. Y.

No Drawing. Application June 20, 1942,

Serial No. 447,749 a 3 Claims. (Cl. 23-128) The present; invention provides an improved process for converting natural magnesium silicates into more readily useful compounds particularly an intermediary a mechanical mix-' ture of silica (S102) with sulphates of magnesium, with sulphates of iron and/or other impurities present in rock used. Said intermediary is in itself a valuable addition product to many fertilizers. Those skilled in the art find that the addition of water readily dissolves the sulphates and the silica quickly settles so that a clear solution of the sulphatescan be drawn off and used for the manufacture of Epsom salts the recovery of any valuable impurities frequently chrome or nickel or as a source of magnesium chloride and/or the metal.

Although magnesium is one of the most common metals in natural rocks, the deposits of soluble compounds and compounds which are In serpentine about one-third of this is readily converted by sulphuric acid into a sulphate.

It is stated in the Wn State Bulletin 3-1940 that serpentine is not considered a, macn'esium ore on account of the cost of separating magnesium from chemical combinations with silica. I

v The present invention has for an object to provide an improved method which can be effectively and economically operated to break the bond between the magnesia and the silica in naturally cc magnesium silicates.

The nature and objects of the invention will he better understood from a description of a particular embodiment thereof.

In any suitable container sulphuric acid is maintained by float or other means to a level at which is secured a needle perforated sheet of lead. on this sheet oi lead serpentine, olivine ground to pass a 40 mesh or finer screen is laid down to a suitable depth, depending on its fineness of grind. In a few hours the sulphuric acid rmeates the mass because otcapillary some tion and the color of the powder darkens and the volume increases and continues to increase for several days as the acid is drawn up as used by its reaction with olivine and the consequent absorption of the water available, either as formed in the reaction or from the dilution of the acid used by the newly formed magnesium sulphate- When the volume ceases to increase there is a cake about four times the height and volume of the ground rock placed on the separating sheet. This cake is light, friable and porous and consists of a mixture of silica with the sulphates of magnesium and of impurities in the rock used.

This cake is easily broken up and may be used as a component in certain fertilizers as is, or as an intermediary for the manufacture of Epsom salts, magnesium chloride or the metal itself.

If the broken up cake is not separated into its parts by a dry method it may be stirred into water which in a few minutes brings the sulphates into a clear solution from which the silica settles and the clear liquid can be drawn ofi and used for any of the purposes above mentioned by any one familiar with the products desired.

5 The silica when washed and dried is in a finely divided state so that about 50% will pass through a 324 sieve, and as a by-product has value. No silica gel is formed in process.

It is desirable to dilute the acid used to about 80 43 B. and chamber acid may be used, and in some cases so-called spent acid from other uses can be brought at a suitable concentration and used. In place of perforated lead any screen of acid resisting nature which meets the requireas ments may be substituted.

The foregoing particular description is illustrative merely and is not intended to defin the limits of the'invention. Variations and modificatime and adaptations may be made without desa parting from the scope of the invention as defined in the claims. For example nitre cake can be used as a substitute for sulphuric acid.

Thisapplication is in part a continuation of applicant's co-pending application, Ser. No.

assess. flied March 11, toes.

I claim:

1'. The method of converting magnesium silt.-

catc to magnesium sulphate which comprises supporting a mass of ar magnesium silicate as above butin contact with a. body of sulphuric acid 2. The .4..=;'.= -1: cif converting; magnesium silt 3 cate to magnesium sulphate which comprises supporting a mass of granular magnesium silicate above but in contact with a body of sulphuric acid in position to take up the sulphuric acid by capillary action, maintaining the level pi the sulphuric acid substantiall constant whereby the acid will be fed-slowly into the mass of silicate at a rate corresponding to the rate oi consumption or the acid.

the horizontal support.

mm B. cmmmzs.